In general, this invention relates to sensor arrays and in particular, to sensor array devices using an infrared detector to measure sensor response. The device is useful in monitoring the physical structure of sensors using infrared thermography.
In general, electronic noses comprise an array of chemical sensing elements and a pattern recognition system. Electronic noses are designed to analyze complex vapors as they exist and produce a unique signature output. The sensor array is designed to respond to many different individual and complex compounds, analytes and vapors. The unique pattern enables the identification of an analyte of interest.
Following the trend that digitized images and sounds give machines the ability to see and hear, digitized odors give machines the ability to smell. Electronic noses are devices that can digitize odors. In certain instances, electronic noses are made of polymer composites and are based on a swell-to-smell mechanism (see, M. Lonergan, E. Severin, B. Doleman, S. Beaber, R. Grubbs, and N. Lewis, Chemistry of Materials, 8 (1996) 2298-2312; and A. Marquez, J. Uribe, and R. Cruz, Journal of Applied Polymer Sciences, 66 (1997) 2221-2232. Certain electronic noses can be easily manufactured into portable devices having affordable prices.
In spite of the advances made in the prior art, devices are needed that can detect analytes using an infrared detector. Moreover, devices and methods are needed that can monitor the manufactured quality of sensors. The present invention fulfills these and other needs.
In certain aspects, the present invention relates to a sensor array device for detecting an analyte in a fluid, comprising: an infrared detector operatively associated with each sensor wherein the detector measures a response in the presence of the analyte. Surprisingly, the inventor has discovered that the use of an infrared detector can monitor a distribution of responses, such as resistances, during exposure of the sensors to various vapors. The infrared detector can monitor changes in the distribution of resistances instead of merely detecting a single overall resistance. A distribution of responses is more indicative of an analyte compared to the overall resistance that is simply a summation of many different resistances. The present invention advantageously measures a matrix of resistances of the sensor array.
In another aspect, the present invention provides a method for monitoring the quality of a sensor, comprising: photographing the sensor with an infrared camera to generate a thermographic image; and analyzing the thermographic image thereby monitoring the quality of the sensor. In certain preferred aspects, the infrared thermographic image is especially useful in a manufacturing area such a quality control, or quality assurance, to monitor the manufacturing quality of sensor arrays.
In yet another aspect, the present invention provides methods for quantitatively predicting the response of the sensor based on its physical structural parameters. Preferably, sensors with a good topographical distribution of polymer(s) are used in the sensor array devices.
In still yet another embodiment, the present invention provides a method for identifying the conducting path of a sensor, comprising: photographing the sensor with an infrared camera to generate a thermographic image; and analyzing the thermographic image thereby identifying the conducting path of the sensor.
In other embodiments, a computer program product is provided that calculates the uniformity of the thermograph, which are generated by the infrared detector.
Numerous advantages are achieved using the present invention over conventional systems. For example, the present system provides enhances resolution of the sensor system. This feature allows unparalleled detection and identification of analytes in an environment. The sensor system of the present invention allows for enhanced resolution that ensures fewer incorrect identifications compared to conventional detectors.